The present invention relates generally to toys and, more particularly, to a toy painted with a paint containing thermochromic material which changes color as the temperature of the toy varies.
In the past, a variety of toys have been developed with color-changing features using thermochromic or light-sensitive materials embedded or mixed in plastic, printed on paper or plastic, or impregnated in fibers used for clothing, doll hair, plush figures, or the like. For example, U.S. Pat. Nos. 4,560,604 issued to Shimizu et al., on Dec. 24, 1985 (coating fibers used for stuffed toys with thermochromic material); 4,134,853 issued to Ehrlich et al. on Jan. 16, 1979 (photochromic composition combined with moldable materials for forming toys); and 3,980,300 issued to Hornsby, Jr. on Sep. 14, 1976 (layer of liquid crystalline material used for ball) which disclose the use of such materials in toys. British Patent No. GB 2,066,089A issued to Rickson on Jul. 8, 1981 describes the use of temperature-sensitive cholesteric liquid crystal material for changing the color of the eyes of a doll. U.S. Pat. No. 3,382,607 issued to Ryan et al. on May 14, 1968 discloses a figure toy having synthetic hair fibers impregnated with an indicator dye which changes color in response to contact with liquids of different pH concentrations.
Thermochromic materials are disclosed in U.S. Pat. Nos. 4,567,019 issued to Lawton on Jan. 28, 1986; 4,421,560 issued to Kito et al. on Dec. 20, 1983; and 4,028,118 issued to Nakasuji et al. on Jun. 7, 1977. Heat-sensitive recording materials are described in U.S. Pat. Nos. 4,611,072 issued to Nachbar et al.; 4,462,616 issued to Shanton on Jul. 31, 1984; and 4,444,819 issued to Maruta et al. A reversible heat sensitive recording composition is disclosed in U.S. Pat. No. 4,720,301 issued to Kito et al. on Jan. 19, 1988.
None of the above patents discloses a toy painted with a paint containing thermochromic material which is capable of changing color as the temperature of the toy varies. A toy such as a miniature die-cast vehicle painted with paint containing thermochromic material provides numerous play options. For example, a child could pretend that such a toy vehicle is being painted by immersing it in heated or cold water causing the color of the vehicle to change. A child could also vary the color of such a vehicle using heated or cold air, ice, heated pens, heated brushes, light bulbs, heat blankets, or the heat of his or her hands. The toy vehicle could be made out of any material such as metal or plastic. Likewise, a toy such as a doll could have portions thereof such as the doll's lips, eyebrows, eyelashes, fingernails, cheeks, etc., painted with paint containing thermochromic material. As a result, a child would be able to vary the color of the doll's lips, eyebrows, eyelashes, etc. by applying hot or cold water to the painted portions of the doll or otherwise changing the temperature of the painted portions, causing the color of the thermochromic material to change. Accordingly, there is a need in the toy manufacturing arts for such a toy.